本发明公开一种提高X80管线钢管焊接接头低温冲击韧性的方法，选择X80厚壁低温管线钢，要求冷裂敏感系数CE(pcm)≤0.19；对经JCOE成型和预焊后的焊管进行精焊，焊接方法采用内外双面双丝四层多道埋弧自动焊的方法，不需要进行预热及焊后热处理，焊接材料采用Mn-Ni-Mo-Ti-B合金系低温焊丝+混合焊剂，每一道的焊接热输入量控制在10～25KJ/cm之间。采用本发明的焊接接头在-45℃时，焊缝中心冲击功平均值≥200J，热影响区冲击功平均值≥300J；-60℃时，焊缝中心冲击功平均值≥180J，热影响区冲击功平均值≥280J，有效提高30～40mm壁厚X80管线钢管焊接接头的低温冲击韧性。

The invention discloses a method for improving the low temperature impact toughness of the welded joint of X80 pipeline steel pipe. X80 thick wall low temperature pipeline steel is selected, and the cold crack sensitivity coefficient CE(PCM) is required to be less than or equal to 0.19. The JCOE forming and pre-welding pipes are refined welded. The welding method is internal and external double-sided double-wire four-layer multi-channel automatic submerged arc welding, without preheating and post-welding heat treatment. The welding material is Mn-Ni-Mo-Ti-B alloy low-temperature welding wire + mixed flux, and the welding heat input of each line is controlled between 10 and 25KJ/cm. At -45℃, the average impact energy in the center of the weld is ≥200J, and the average impact energy in the heat affected zone is ≥300J. At -60℃, the average impact energy in the weld center is ≥180J, and the average impact energy in the heat affected zone is ≥280J, which can effectively improve the low temperature impact toughness of the welded joints of X80 pipeline pipe with 30-40mm wall thickness.